Method for Implementing Point-To-Multipoint Multicast, Network Node, and System

ABSTRACT

Embodiments of the present invention provide a method for implementing P2MP multicast, a network node, and a system. The method includes: acquiring, by a network-side leaf node, an mLDP label of a downstream user-side leaf node and FEC information from an mLDP mapping message of the downstream user-side leaf node, then sending an mLDP mapping message that includes an mLDP label and the FEC information, to an upstream network-side root node, and generating a forwarding entry; searching for or establishing an RSVP P2MP LSP, allocating a label to the FEC information, and associating a forwarding entry of each network-side leaf node with the label of the FEC information; and sending an mLDP label of the network-side root node and the FEC information to an upstream user-side leaf node, and associating the mLDP label with the RSVP P2MP LSP and the label of the FEC information.

This application is a continuation of International Application No.PCT/CN2013/075598, filed on May 14, 2013, which claims priority toChinese Patent Application No. 201210375288.1, filed on Sep. 29, 2012,both of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the communications field, and inparticular, to a method for implementing point-to-multipoint multicast,a network node, and a system.

BACKGROUND

With development of an Internet Protocol, Internet Protocol (IP)network, more and more applications use the IP network to perform datatransmission. Data transmission of applications such as multimediaconferencing, real-time online gaming, and IP Television (IPTV) has apoint-to-multipoint (or multipoint-to-multipoint) feature.

Compared with a unicast data transmission mode of the IP network, an IPmulticast technology implements point-to-multipoint data transmission inthe IP network. For multiple data receiving nodes, it is unnecessary toreplicate all traffic of data at a sending end; instead, traffic isreplicated at a corresponding node as required according to an IPforwarding path in the network. On the whole, only one piece of data istransmitted on any link in the network, until the data arrives at thereceiving nodes. Therefore, compared with IP unicast transmission, IPmulticast transmission has a remarkably lower requirement for networkbandwidth, so that highest data transmission efficiency is achieved inthe network. IP multicast transmission requires cooperation of a controlplane in the network, which is completed by a corresponding multicastprotocol, for example, Protocol Independent Multicast-Sparse Mode(PIM-SM) or Protocol Independent Multicast Source Specific Multicast(PIM-SSM). After protocol interaction, the IP network establishes atransmission path for multicast data, thereby achieving objectives of anoptimal path and least bandwidth usage.

However, in terms of supporting real-time applications such as IPTV andstreaming media, there are still restrictions for IP multicast, such asa bandwidth guarantee and failover, which restrict large-scaledeployment of the applications. As the Multi Protocol Label Switching(MPLS) technology is deployed on a large scale, failover can beimplemented and bandwidth requirements can be met. Therefore, thePoint-to-MultiPoint (P2MP) multicast technology base on MPLS has becomea hot topic currently.

Currently, the MPLS P2MP technology mainly includes two types: ResourceReservation Protocol (RSVP) P2MP and multicast Label DistributionProtocol (mLDP) P2MP. The former is an extension based on apoint-to-point RSVP protocol, and the latter is an extension based on apoint-to-point LDP protocol. A purpose of the MPLS P2MP technology is toestablish a point-to-multipoint (or multipoint-to-multipoint) forwardingpath for data forwarding.

According to an existing solution, in a P2MP-based multicast VirtualPrivate Network (VPN) application proposed by an Internet EngineeringTask Force (IETF) draft, a core network establishes RSVP P2MP Path,while mLDP is used for access between each Provider Edge (PE) node andeach Customer Edge (CE), and multicast traffic of a private network istransmitted through mLDP P2MP forwarding paths at two ends and a coreRSVP P2MP forwarding path. In this way, mLDP may access P2MP. However,this application is an application that accesses the VPN. VPNnegotiation needs to be performed at the control plane based on acomplicated protocol, and a forwarding entry of a PE node must beestablished based on VPN information. Therefore, this solution is notapplicable to a P2MP multicast scenario of a non-VPN application.Furthermore, in an existing multicast scenario, a PE node must performmLDP protocol processing, and implementation thereof is complicated, andwhen a PE device does not support mLDP, deployment cannot beimplemented.

SUMMARY

Embodiments of the present invention provide a method for implementingpoint-to-multipoint multicast, a network node, and a system, which canbe applied to P2MP multicast in a non-VPN scenario and can alsoimplement deployment when a PE device does not support mLDP.

To achieve the foregoing objective, the embodiments of the presentinvention use the following technical solutions:

According to a first aspect, a method for implementingpoint-to-multipoint multicast is provided, where the method includes:

receiving an mLDP mapping message from at least one downstream node,where each mLDP mapping message includes forwarding equivalence classFEC information and an mLDP label of a node to which the mLDP mappingmessage belongs;

acquiring a Resource Reservation Protocol point-to-multipoint path RSVPP2MP LSP according to the downstream nodes that send the mLDP mappingmessages;

allocating a label to the FEC information, and sending the label of theFEC information to all the nodes that are on the RSVP P2MP LSP and sendthe mLDP mapping messages;

generating a packet forwarding entry of a local node according to anmLDP label of the local node, the RSVP P2MP LSP, and the label of theFEC information; and

sending a new mLDP mapping message to an upstream node, where the newmLDP mapping message includes the FEC information and the mLDP label ofthe local node, and the FEC information includes an address of auser-side root node.

With reference to the first aspect, in a first possible implementationmanner, the acquiring an RSVP P2MP LSP according to the downstream nodesthat send the mLDP mapping messages includes:

searching for an existing RSVP P2MP LSP according to the downstreamnodes that send the mLDP mapping messages; or

establishing the RSVP P2MP LSP according to the downstream nodes thatsend the mLDP mapping messages,

where the RSVP P2MP LSP includes all the downstream nodes that send themLDP mapping messages.

With reference to the first aspect or the first possible implementationmanner of the first aspect, in a second possible implementation manner,the allocating a label to the FEC information, and sending the label ofthe FEC information to all the nodes that are on the RSVP P2MP LSP andsend the mLDP mapping messages include:

sending a distribution message that includes the FEC information and thelabel of the FEC information to an intermediate node, so that theintermediate node sends, after replicating the distribution message, thedistribution message to all the nodes that are on the RSVP P2MP LSP andsend the mLDP mapping messages; or

after connections are established to all the nodes that are on the RSVPP2MP LSP and send the mLDP mapping messages, sending a distributionmessage directly to all the nodes that are on the RSVP P2MP LSP and sendthe mLDP mapping messages, so that all the nodes that send the mLDPmapping messages use the label of the FEC information as an incominglabel of packet forwarding entries of the nodes.

With reference to the first aspect, or the first possible implementationmanner of the first aspect, or the second possible implementation mannerof the first aspect, in a third possible implementation manner, thegenerating a packet forwarding entry of a local node according to anmLDP label of the local node, the RSVP P2MP LSP, and the label of theFEC information includes:

associating the mLDP label of the local node with the RSVP P2MP LSP andthe label of the FEC information, and generating the packet forwardingentry of the local node, where the mLDP label of the local node is setas an incoming label, and an RSVP label of a downstream node that sendsthe mLDP mapping message is set as an outgoing label, where the RSVPlabel of the downstream node that sends the mLDP mapping message isallocated when the RSVP P2MP LSP is established.

With reference to the first aspect, or the first possible implementationmanner of the first aspect to the third possible implementation mannerof the first aspect, in a fourth possible implementation manner, themethod further includes:

receiving a multi-protocol label switching packet from an upstream node,where the multi-protocol label switching packet is encapsulated by theuser-side root node by using an mLDP label of the local node;

removing the mLDP label of the local node from the multi-protocol labelswitching packet;

replicating the multi-protocol label switching packet with the mLDPlabel removed, where the number of replicated multi-protocol labelswitching packets is equal to the number of outgoing labels in thepacket forwarding entry of the local node; and

encapsulating the replicated multi-protocol label switching packet byusing the label of the FEC information and an RSVP label of a downstreamnode that sends an mLDP mapping message, where the label of the FECinformation is used as an inner label, and the RSVP label of thedownstream node that sends the mLDP mapping message is used as an outerlabel, and sending the multi-protocol label switching packet to thedownstream node corresponding to the RSVP label of the downstream nodethat sends the mLDP mapping message.

According to a second aspect, a method for implementingpoint-to-multipoint multicast is provided, where the method includes:

receiving an mLDP mapping message, which is sent by a user-side leafnode and forwarded by at least one network-side leaf node;

performing snooping on the received mLDP mapping message to acquire,from the mLDP mapping message, FEC information and an mLDP label of auser-side leaf node to which the mLDP mapping message belongs;

acquiring a Resource Reservation Protocol point-to-multipoint path RSVPP2MP LSP according to the network-side leaf nodes;

allocating a label to the FEC information, and sending the label of theFEC information to all the nodes that are on the RSVP P2MP LSP andforward the mLDP mapping messages;

generating a packet forwarding entry of the local node according to anmLDP label in the 1^(st) mLDP mapping message received by the localnode, the RSVP P2MP LSP, and the label of the FEC information; and

forwarding the 1^(st) mLDP mapping message among received mLDP mappingmessages that belong to the same FEC information, to an upstream node.

With reference to the second aspect, in a first possible implementationmanner, the method further includes:

receiving a multi-protocol label switching packet from an upstream node,where the multi-protocol label switching packet is encapsulated by auser-side root node by using the mLDP label of the user-side leaf node;

removing the mLDP label of the user-side leaf node from themulti-protocol label switching packet;

replicating the multi-protocol label switching packet with the mLDPlabel removed, where the number of replicated multi-protocol labelswitching packets is equal to the number of outgoing labels in thepacket forwarding entry of the network-side root node; and

encapsulating the replicated multi-protocol label switching packet byusing the label of the FEC information and an RSVP label of a downstreamnode that forwards the mLDP mapping message, where the label of the FECinformation is used as an inner label, and the RSVP label of thedownstream node that forwards the mLDP mapping message is used as anouter label, and sending the multi-protocol label switching packet tothe downstream node corresponding to the RSVP label of the node.

According to a third aspect, a method for implementingpoint-to-multipoint multicast is provided, where the method includes:

receiving a distribution message that includes FEC information and alabel of the FEC information from an upstream network-side root node;

sending a response message to the network-side root node; and

using the label of the FEC information as an incoming label of a packetforwarding entry of a local node.

With reference to the third aspect, in a first possible implementationmanner, the receiving a distribution message that includes FECinformation and a label of the FEC information from an upstreamnetwork-side root node includes:

receiving, from an intermediate node, the distribution message sent bythe network-side root node; or

after a connection is established to the network-side root node on anRSVP P2MP LSP, receiving the distribution message directly from thenetwork-side root node.

With reference to the third aspect or the first possible implementationmanner of the third aspect, in a second possible implementation manner,the method further includes:

receiving a multi-protocol label switching packet from the upstreamnetwork-side root node;

removing an RSVP label of the local node from the multi-protocol labelswitching packet, and removing the label of the FEC information from areplicated multi-protocol label switching packet, where the RSVP labelof the local node is allocated when the local node establishes the RSVPP2MP LSP to the network-side root node;

replicating the multi-protocol label switching packet with the RSVPlabel and the label of the FEC information removed, where the number ofreplicated multi-protocol label switching packets is determinedaccording to the number of mLDP labels of downstream nodes correspondingto the label of the FEC information; and

encapsulating the replicated multi-protocol label switching packet byusing an mLDP label in an mLDP mapping message sent by a downstreamnode, and sending the multi-protocol label switching packet to thedownstream node corresponding to the mLDP label of the downstream node.

According to a fourth aspect, a network node is provided, where the nodeincludes:

a first receiving unit, configured to receive an mLDP mapping messagefrom at least one downstream node, where each mLDP mapping messageincludes forwarding equivalence class FEC information and an mLDP labelof a node to which the mLDP mapping message belongs, and send each mLDPmapping message to a first label allocating unit and a first entrycreating unit;

a first path acquiring unit, configured to acquire an RSVP P2MP LSPaccording to the downstream nodes that send the mLDP mapping messages,and send information about the RSVP P2MP LSP to the first labelallocating unit and the first entry creating unit;

the first label allocating unit, configured to receive each mLDP mappingmessage from the first receiving unit, receive the information about theRSVP P2MP LSP from the first path acquiring unit, allocate a label tothe FEC information, and send the label of the FEC information to allthe nodes that are on the RSVP P2MP LSP and send the mLDP mappingmessages;

the first entry creating unit, configured to receive each mLDP mappingmessage from the first receiving unit, receive the information about theRSVP P2MP LSP from the first path acquiring unit, and according to anmLDP label of the local node, the RSVP P2MP LSP, and the label of theFEC information, generate a packet forwarding entry of the local node;and

a first sending unit, configured to send a new mLDP mapping message toan upstream node, where the new mLDP mapping message includes the FECinformation and the mLDP label of the local node, and the FECinformation includes an address of a user-side root node.

With reference to the fourth aspect, in a first possible implementationmanner, the first path acquiring unit is specifically configured to:

search for an existing RSVP P2MP LSP according to the downstream nodesthat send the mLDP mapping messages; or

establish the RSVP P2MP LSP according to the downstream nodes that sendthe mLDP mapping messages,

where the RSVP P2MP LSP includes all the downstream nodes that send themLDP mapping messages.

With reference to the fourth aspect or the first possible implementationmanner of the fourth aspect, in a second possible implementation manner,the first label allocating unit is specifically configured to:

send a distribution message that includes the FEC information and thelabel of the FEC information to an intermediate node, so that theintermediate node sends, after replicating the distribution message, thedistribution message to all the nodes that are on the RSVP P2MP LSP andsend the mLDP mapping messages; or

after connections are established to all the nodes that are on the RSVPP2MP LSP and send the mLDP mapping messages, send a distribution messagedirectly to all the nodes that are on the RSVP P2MP LSP and send themLDP mapping messages, so that all the nodes that send the mLDP mappingmessages use the label of the FEC information as an incoming label ofpacket forwarding entries of the nodes.

With reference to the fourth aspect, or the first possibleimplementation manner of the fourth aspect, or the second possibleimplementation manner of the fourth aspect, in a third possibleimplementation manner, the first entry creating unit is specificallyconfigured to:

associate the mLDP label of the local node with the RSVP P2MP LSP andthe label of the FEC information, and generate the packet forwardingentry of the local node, where the mLDP label of the local node is setas an incoming label, and an RSVP label of a downstream node that sendsthe mLDP mapping message is set as an outgoing label, where the RSVPlabel of the downstream node that sends the mLDP mapping message isallocated when the RSVP P2MP LSP is established.

With reference to the fourth aspect, or any one of the first possibleimplementation manner of the fourth aspect to the third possibleimplementation manner of the fourth aspect, in a fourth possibleimplementation manner,

the first receiving unit, further configured to receive a multi-protocollabel switching packet from an upstream node, where the multi-protocollabel switching packet is encapsulated by the user-side root node byusing an mLDP label of the local node; and the node further includes:

a first label processing unit, configured to remove the mLDP label ofthe local node from the multi-protocol label switching packet, and sendthe multi-protocol label switching packet with the mLDP label removed,to a first packet replicating unit; and

the first packet replicating unit, configured to receive, from the firstlabel processing unit, the multi-protocol label switching packet withthe mLDP label removed, replicate the multi-protocol label switchingpacket with the mLDP label removed, where the number of replicatedmulti-protocol label switching packets is equal to the number ofoutgoing labels in the packet forwarding entry of the local node, andsend the replicated multi-protocol label switching packets to the firstlabel processing unit, where

the first label processing unit is further configured to receive thereplicated multi-protocol label switching packets from the first packetreplicating unit, encapsulate the replicated multi-protocol labelswitching packet by using the label of the FEC information and an RSVPlabel of a downstream node that sends an mLDP mapping message, where thelabel of the FEC information is used as an inner label, and the RSVPlabel of the downstream node that sends the mLDP mapping message is usedas an outer label, and send, by using the first sending unit, themulti-protocol label switching packet to the downstream nodecorresponding to the RSVP label of the downstream node that sends themLDP mapping message.

According to a fifth aspect, a network node is provided, where the nodeincludes:

a second receiving unit, configured to receive an mLDP mapping message,which is sent by a user-side leaf node and forwarded by at least onedownstream node, and send the received mLDP mapping message to a messagesnooping unit;

the message snooping unit, configured to receive the mLDP mappingmessage from the second receiving unit, perform snooping on the receivedmLDP mapping message to acquire, from the mLDP mapping message, FECinformation and an mLDP label of the user-side leaf node to which themLDP mapping message belongs, and send the message undergoing thesnooping to a second label allocating unit and a second entry creatingunit;

a second path acquiring unit, configured to acquire a ResourceReservation Protocol point-to-multipoint path RSVP P2MP LSP;

the second label allocating unit, configured to receive, from the secondreceiving unit, the message undergoing the snooping, allocate a label tothe FEC information, and send the label of the FEC information to allthe nodes that forward the mLDP mapping message and are on the RSVP P2MPLSP;

the second entry creating unit, configured to receive, from the secondreceiving unit, the message undergoing the snooping, and according to anmLDP label in the 1st mLDP mapping message received by the local node,the RSVP P2MP LSP, and the label of the FEC information, generate apacket forwarding entry of the local node; and

a second sending unit, configured to forward the 1st mLDP mappingmessage among received mLDP mapping messages that belong to the same FECinformation, to an upstream node.

With reference to the fifth aspect, in a first possible implementationmanner, the second entry creating unit is specifically configured to:

associate the mLDP label in the 1st mLDP mapping message received by thelocal node with the RSVP P2MP LSP and the label of the FEC information,and generate the packet forwarding entry of the network-side root node,where the mLDP label in the 1st mLDP mapping message received by thelocal node is set as an incoming label, and an RSVP label of adownstream node that forwards the mLDP mapping message is set as anoutgoing label, where the RSVP label of the lower-level node of thelocal node is allocated when the RSVP P2MP LSP is established.

With reference to the fifth aspect or the first possible implementationmanner of the fifth aspect, in a second possible implementation manner,the method further includes:

the second receiving unit, further configured to receive amulti-protocol label switching packet from an upstream node, where themulti-protocol label switching packet is encapsulated by a user-sideroot node by using the mLDP label of the user-side leaf node;

a second label processing unit, configured to remove the mLDP label ofthe user-side leaf node from the multi-protocol label switching packet,and send the multi-protocol label switching packet with the mLDP labelremoved, to a second packet replicating unit; and

the second packet replicating unit, configured to receive, from thesecond label processing unit, the multi-protocol label switching packetwith the mLDP label removed, replicate the multi-protocol labelswitching packet with the mLDP label removed, where the number ofreplicated multi-protocol label switching packets is equal to the numberof outgoing labels in the packet forwarding entry of a network-side rootnode, and send the replicated multi-protocol label switching packets tothe second label processing unit, where:

the second label processing unit is further configured to receive thereplicated multi-protocol label switching packets from the second packetreplicating unit, encapsulate the replicated multi-protocol labelswitching packet by using the label of the FEC information and the RSVPlabel of the downstream node that forwards the mLDP mapping message,where the label of the FEC information is used as an inner label, andthe RSVP label of the downstream node that forwards the mLDP mappingmessage is used as an outer label, and send the multi-protocol labelswitching packet to the downstream node corresponding to the RSVP labelof the node.

According to a sixth aspect, a network node is provided, where the nodeincludes:

a third receiving unit, configured to receive, from an upstream node adistribution message, wherein the distribution message includes FECinformation and a label of the FEC information, and send thedistribution message to a third label processing unit;

a third sending unit, configured to send a response message to theupstream node that sends the distribution message; and

the third label processing unit, configured to receive the distributionmessage from the third receiving unit, and use the label of the FECinformation as an incoming label of a packet forwarding entry of thelocal node.

With reference to the sixth aspect, in a first possible implementationmanner, the third receiving unit is specifically configured to:

receive, from an intermediate node, the distribution message sent by thenetwork-side root node; or

after a connection is established to the network-side root node on anRSVP P2MP LSP, receive the distribution message directly from thenetwork-side root node.

With reference to the sixth aspect or the first possible implementationmanner of the sixth aspect, in a second possible implementation manner,the method further includes:

the third receiving unit, further configured to receive a multi-protocollabel switching packet from the upstream network-side root node;

the third label processing unit, further configured to remove an RSVPlabel of the local node from the multi-protocol label switching packet,and remove the label of the FEC information from a replicatedmulti-protocol label switching packet, where the RSVP label of the localnode is allocated when the RSVP P2MP LSP is established;

a third packet replicating unit, configured to replicate themulti-protocol label switching packet with the RSVP label and the labelof the FEC information removed, where the number of replicatedmulti-protocol label switching packets is determined according to thenumber of mLDP labels of downstream nodes corresponding to the label ofthe FEC information, and send the replicated multi-protocol labelswitching packets to the third label processing unit; and

the third label processing unit, further configured to receive thereplicated multi-protocol label switching packets from the third packetreplicating unit, encapsulate the replicated multi-protocol labelswitching packet by using an mLDP label in an mLDP mapping message sentby a downstream node, and send, by using the third sending unit, themulti-protocol label switching packet to the downstream nodecorresponding to the mLDP label of the downstream node.

Embodiments of the present invention provide a method for implementingpoint-to-multipoint multicast, a network node, and a system. Anetwork-side root node acquires an RSVP P2MP LSP, allocates a labelvalue to received FEC information, and associates a forwarding entry ofeach network-side leaf node with the label value of the FEC information;meanwhile, the network-side root node sends an mLDP label of thenetwork-side root node and the FEC information to an upstream user-sideleaf node by using an mLDP mapping message, and associates the mLDPlabel of the network-side root node with the RSVP P2MP LSP and the labelof the FEC information. Alternatively, the network-side root nodeacquires FEC information and an mLDP label by performing snooping, andacquires an RSVP P2MP LSP, and then allocates a label value to thereceived FEC information, and associates a forwarding entry of eachnetwork-side leaf node with the label of the FEC information; meanwhile,the network-side root node transparently transmits a first received mLDPmapping message to an upstream node, and associates an mLDP label in themLDP mapping message with the RSVP P2MP LSP and the label of the FECinformation. In this way, an mLDP over RSVP point-to-multipointmulticast path is established, which is applicable to P2MP multicast ina non-VPN scenario. Because the node may perform snooping to acquire FECinformation and an mLDP label of a downstream node from an mLDP mappingmessage, it is not necessary for each node to completely support mLDP,so that deployment can also be implemented when a node does not supportmLDP. Further, during packet forwarding, excessive packet replicationcan be avoided, and bandwidth resources can be saved. In addition,message suppression processing is performed on mLDP mapping messagesthat include the same FEC information, which further saves bandwidth andreduces processing load of the node.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentinvention more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments or theprior art. Apparently, the accompanying drawings in the followingdescription show merely some embodiments of the present invention, and aperson of ordinary skill in the art may still derive other drawings fromthese accompanying drawings without creative efforts.

FIG. 1 is a first schematic flowchart of a method for implementingpoint-to-multipoint multicast according to an embodiment of the presentinvention;

FIG. 2 is a second schematic flowchart of a method for implementingpoint-to-multipoint multicast according to an embodiment of the presentinvention;

FIG. 3 is a third schematic flowchart of a method for implementingpoint-to-multipoint multicast according to an embodiment of the presentinvention;

FIG. 4 is a first schematic flowchart of a method for implementingpoint-to-multipoint multicast according to another embodiment of thepresent invention;

FIG. 5 is a second schematic flowchart of a method for implementingpoint-to-multipoint multicast according to another embodiment of thepresent invention;

FIG. 6 is a third schematic flowchart of a method for implementingpoint-to-multipoint multicast according to another embodiment of thepresent invention;

FIG. 7 is a fourth schematic flowchart of a method for implementingpoint-to-multipoint multicast according to another embodiment of thepresent invention;

FIG. 8 is a schematic diagram of a protection effect of apoint-to-multipoint multicast link according to another embodiment;

FIG. 9 is a first schematic structural diagram of a network nodeaccording to an embodiment of the present invention;

FIG. 10 is a second schematic structural diagram of a network nodeaccording to an embodiment of the present invention;

FIG. 11 is a first schematic structural diagram of another network nodeaccording to an embodiment of the present invention;

FIG. 12 is a second schematic structural diagram of another network nodeaccording to an embodiment of the present invention;

FIG. 13 is a first schematic structural diagram of still another networknode according to an embodiment of the present invention;

FIG. 14 is a second schematic structural diagram of still anothernetwork node according to an embodiment of the present invention;

FIG. 15 is a schematic structural diagram of an edge device according toan embodiment of the present invention;

FIG. 16 is a schematic structural diagram of another edge deviceaccording to an embodiment of the present invention;

FIG. 17 is a schematic structural diagram of still another edge deviceaccording to an embodiment of the present invention;

FIG. 18 is a schematic structural diagram of a communications systemaccording to an embodiment of the present invention; and

FIG. 19 is a schematic structural diagram of another communicationssystem according to an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following clearly and completely describes the technical solutionsin the embodiments of the present invention with reference to theaccompanying drawings in the embodiments of the present invention.Apparently, the described embodiments are merely a part rather than allof the embodiments of the present invention. All other embodimentsobtained by a person of ordinary skill in the art based on theembodiments of the present invention without creative efforts shall fallwithin the protection scope of the present invention.

A multicast source communicates with multicast receivers by using anetwork running mLDP and a network running RSVP. The network runningRSVP includes a multicast source-oriented PE node, which is referred toas a network-side root node, and further includes multicastreceivers-oriented PE nodes, which are referred to as network-side leafnodes. The network-side root node communicates with the multicast sourceby using the network running mLDP. The network-side leaf nodescommunicate with the multicast receivers by using the network runningmLDP. A PE node that is in the network running mLDP and is oriented tothe multicast source is referred to as a user-side root node, and PEnodes that are in the network running mLDP and are oriented to themulticast receivers are referred to as user-side leaf nodes. Anembodiment of the present invention provides a method for implementingpoint-to-multipoint multicast. As shown in FIG. 1, the method includes:

101. The network-side root node receives an mLDP mapping message from atleast one downstream network-side leaf node, where each mLDP mappingmessage includes forwarding equivalence class (FEC) information and anmLDP label of a network-side leaf node that sends the mLDP mappingmessage; and the FEC information includes an address of the user-sideroot node.

For example, the network running RSVP includes three network-side leafnodes, and the network-side root node receives three mLDP mappingmessages, where each mLDP mapping message includes the same FECinformation.

102. The network-side root node acquires a Resource Reservation Protocolpoint-to-multipoint path (RSVP P2MP LSP) according to the network-sideleaf node that sends the mLDP mapping message.

103. The network-side root node allocates a label of FEC information tothe FEC information, and sends the label of the FEC information to allthe network-side leaf nodes that are on the RSVP P2MP LSP and send themLDP mapping messages.

For example, when three mLDP mapping messages are received in theforegoing 101, where each mLDP mapping message includes the same FECinformation, the network-side root node allocates a label to the FECinformation.

104. The network-side root node generates a packet forwarding entry ofthe network-side root node according to an mLDP label of thenetwork-side root node, the RSVP P2MP LSP, and the label of the FECinformation.

105. The network-side root node sends a new mLDP mapping message to theupstream user-side root node, where the new mLDP mapping messageincludes the FEC information and the mLDP label of the network-side rootnode, and the FEC information includes the address of the user-side rootnode.

An embodiment of the present invention provides another method forimplementing point-to-multipoint multicast. As shown in FIG. 2, based ona network-side root node, the method includes:

201. The network-side root node receives an mLDP mapping message, whichis sent by a user-side leaf node and forwarded by at least onenetwork-side leaf node, where the mLDP mapping message includes FECinformation and an mLDP label of the user-side leaf node that sends themLDP mapping message.

202. The network-side root node acquires, from the mLDP mapping message,the FEC information and the mLDP label of the user-side leaf node thatsends the mLDP mapping message.

203. The network-side root node acquires a Resource Reservation Protocolpoint-to-multipoint path (RSVP P2MP LSP) according to the user-side leafnode that sends the mLDP mapping message.

For example, when a network-side leaf node transparently transmits anmLDP mapping message, the network-side leaf node may notify thenetwork-side root node by using a protocol message to indicate that thenetwork-side leaf node is a leaf node, for example, by using a BGPprotocol-based RSVP P2MP leaf discovery technology or by using thedistribution protocol described in this specification.

204. The network-side root node allocates a label of FEC information tothe FEC information, and sends the label of the FEC information to allthe network-side leaf nodes that are on the RSVP P2MP LSP and forwardthe mLDP mapping message.

205. The network-side root node generates a packet forwarding entry ofthe network-side root node according to an mLDP label in the 1st mLDPmapping message received by the network-side root node, the RSVP P2MPLSP, and the label of the FEC information.

206. The network-side root node forwards the first mLDP mapping messageamong received mLDP mapping messages that belong to the same FECinformation, to a user-side root node.

An embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. As shown in FIG. 3, based ona network-side leaf node, the method includes:

301. The network-side leaf node receives a distribution message from anetwork-side root node, where the distribution message includes FECinformation and a label of the FEC information.

302. The network-side leaf node sends a response message to thenetwork-side root node.

303. The network-side leaf node uses the label of the FEC information asan incoming label of a packet forwarding entry of the network-side leafnode.

The embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. A network-side root nodeacquires an RSVP P2MP LSP, allocates a label to received FECinformation, and associates a forwarding entry of each network-side leafnode with the label of the FEC information; meanwhile, the network-sideroot node sends an mLDP label of the network-side root node and the FECinformation to an upstream user-side leaf node by using an mLDP mappingmessage, and associates the mLDP label of the network-side root nodewith the RSVP P2MP LSP and the label of the FEC information.Alternatively, the network-side root node acquires FEC information andan mLDP label by snooping, acquires an RSVP P2MP LSP, then allocates alabel to received FEC information, and associates a forwarding entry ofeach network-side leaf node with the label of the FEC information;meanwhile, the network-side root node transparently transmits the 1streceived mLDP mapping message to a user-side root node, and associatesan mLDP label in the mLDP mapping message with the RSVP P2MP LSP and thelabel of the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Because the node can acquireFEC information and an mLDP label of a downstream node from the mLDPmapping message by performing snooping on an mLDP mapping message, it isnot necessary for each node to completely support mLDP, so thatdeployment can also be implemented when a node does not support mLDP.Further, during packet forwarding, excessive packet replication can beavoided, and bandwidth resources can be saved. In addition, messagesuppression processing is performed on mLDP mapping messages thatinclude the same FEC information, which further saves bandwidth andreduces processing load of the node.

Another embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. It is assumed that: anupper-level node of a user-side leaf node is a network-side leaf node,an upper-level node of the network-side leaf node is a network-side rootnode, and an upper-level node of the network-side root node is auser-side root node. As shown in FIG. 4, the method includes:

401. After receiving a multicast join request message sent by adownstream node, a user-side leaf node acquires an address of auser-side root node according to address information of a multicastsource in the multicast join request message.

Specifically, the user-side leaf node may be, for example, a U-PE (leaf)node, where the U-PE refers to User-Provider Edge (user-side edgedevice). After receiving the multicast join request message sent by thedownstream node, for example, PIM-SSM join, the U-PE (leaf) nodeinitiates establishment of an mLDP P2MP LSP, and according to a sourceaddress in a multicast protocol, may perform internal iteration based ona routing table to obtain the address of the user-side root node, whichmay be, for example, an address of a U-PE (root) node.

402. The user-side leaf node generates a first mLDP mapping message,where the first mLDP mapping message includes FEC information and anmLDP label of the user-side leaf node, and the FEC information includesthe address of the user-side root node.

Exemplarily, the U-PE (leaf) node first allocates an mLDP label to theU-PE (leaf) node itself, and then constructs a first mLDP mappingmessage, where the first mLDP mapping message includes the FECinformation and the mLDP label of the U-PE (leaf) node, and the FECinformation may include the address of the U-PE (root) node.

After generating the first mLDP mapping message, the user-side leaf nodemay send the first mLDP mapping message to an upstream network-side leafnode. The network-side leaf node may be an N-PE (leaf) node, where theN-PE refers to Net-Provider Edge (network-side edge device).

403. The network-side leaf node receives the first mLDP mapping messagefrom at least one downstream user-side leaf node.

Exemplarily, because of point-to-multipoint, the N-PE (leaf) node mayhave multiple downstream U-PE (leaf) nodes. Therefore, the first mLDPmapping messages received by the N-PE (leaf) node may be sent bymultiple U-PE (leaf) nodes. A first mLDP mapping message sent by eachU-PE (leaf) node includes the FEC information and an mLDP label value ofthe U-PE (leaf) that sends the first mLDP mapping message, and the FECinformation includes the address of the U-PE (root) node.

404. The network-side leaf node acquires an address of a network-sideroot node according to the address of the user-side root node in the FECinformation.

Exemplarily, the N-PE (leaf) node may perform iteration according to theaddress of the U-PE (root) node in the FEC information and routing tableinformation to obtain the address of the network-side root node, wherethe network-side root node may be an N-PE (root) node.

405. The network-side leaf node generates a second mLDP mapping message,where the second mLDP mapping message includes the FEC information andan mLDP label of the network-side leaf node, and the FEC informationincludes the address of the user-side root node.

Exemplarily, the N-PE (leaf) node first allocates an mLDP label to theN-PE (leaf) node itself, and then constructs a second mLDP mappingmessage, where the second mLDP mapping message includes the FECinformation and the mLDP label of the N-PE (leaf) node, and the FECinformation may include the address of the U-PE (root) node.

After generating the second mLDP mapping message, the network-side leafnode may send the second mLDP mapping message to the upstreamnetwork-side root node. It should be noted that, the upstream node ofthe network-side leaf node may be not the network-side root node, forexample, it may be an intermediate node; in this case, the second mLDPmapping message needs to be first sent to the intermediate node, andthen is forwarded by the intermediate node to the upstream node layer bylayer until the second mLDP mapping message arrives at the network-sideroot node.

406. The network-side leaf node generates a packet forwarding entry ofthe network-side leaf node according to the mLDP label of thenetwork-side leaf node and the mLDP labels of all the user-side leafnodes that send the first mLDP mapping messages.

Exemplarily, the mLDP label of the N-PE (leaf) node may be set as anincoming label, and the mLDP labels of all the U-PE (leaf) nodes thatsend the first mLDP mapping messages are set as outgoing labels, so thata packet forwarding entry of the N-PE (leaf) node is generated. Itshould be noted that, sending the second mLDP mapping message to theupstream N-PE (root) node and creating the packet forwarding entry ofthe local node may be performed at the same time.

407. The network-side root node receives the second mLDP mapping messagefrom at least one downstream network-side leaf node.

Exemplarily, the network-side root node may be the N-PE (root) node.Because of point-to-multipoint, the N-PE (root) node may have multipledownstream N-PE (leaf) nodes. Therefore, the second mLDP mappingmessages received by the N-PE (root) node may be sent by multiple N-PE(leaf) nodes. The second mLDP mapping message sent by each N-PE (leaf)node includes the FEC information and an mLDP label value of the N-PE(leaf) that sends the second mLDP mapping message, and the FECinformation includes the address of the U-PE (root) node.

408. The network-side root node acquires an RSVP P2MP LSP according tothe downstream network-side leaf nodes that send the second mLDP mappingmessages.

Specifically, the network-side root node may search for an existing RSVPP2MP LSP or establish an RSVP P2MP LSP, where the RSVP P2MP LSP includesall the network-side leaf nodes that send the second mLDP mappingmessages.

Exemplarily, the N-PE (root) node may first search for a proper RSVPP2MP LSP among existing RSVP P2MP LSPs, where the RSVP P2MP LSP caninclude all the downstream N-PE (leaf) nodes that send the second mLDPmapping messages. If no RSVP P2MP LSP meeting the foregoing conditionexists among the existing RSVP P2MP LSPs, a new RSVP P2MP LSP isestablished, so that the new RSVP P2MP LSP can include all thedownstream N-PE (leaf) nodes that send the second mLDP mapping messages.

409. The network-side root node allocates a label of FEC information tothe FEC information in the second mLDP mapping messages, and sends thelabel of the FEC information to all the network-side leaf nodes on theRSVP P2MP LSP.

Exemplarily, after finding or establishing the proper RSVP P2MP LSP, theN-PE (root) node allocates a label of FEC information to the FECinformation in the second mLDP mapping messages, where the label of theFEC information is an index value of the FEC information. It should benoted that, one label is allocated to one piece of FEC information.Therefore, if the second mLDP mapping messages sent by the downstreamN-PE (leaf) nodes include same FEC information, one label of FECinformation is allocated to the same FEC information. If the second mLDPmapping messages sent by the downstream N-PE (leaf) nodes includedifferent FEC information, the number of allocated labels of FECinformation is equal to the number of pieces of different FECinformation.

After allocating the label to the FEC information is completed, thenetwork-side root node sends the label of the FEC information to all thedownstream network-side leaf nodes on the RSVP P2MP LSP. For example, aspecific implementation manner may be as follows:

In a first manner, the network-side root node sends a distributionmessage to an intermediate node, and then the intermediate node sends,after replicating the distribution message, the distribution message toall the N-PE (leaf) nodes on the RSVP P2MP LSP. An advantage of thismanner is that the N-PE (root) node needs only to send one distributionmessage to the downstream. The distribution message includes the FECinformation and the label of the FEC information.

Alternatively, in a second manner, the N-PE (root) node may separatelyestablish connections to all the N-PE (leaf) nodes on the RSVP P2MP LSP,and after the connections are established, directly send thedistribution message in a unicast manner to all the N-PE (leaf) nodes onthe RSVP P2MP LSP, so that all the N-PE (leaf) nodes replace the mLDPlabels of the nodes in the packet forwarding entries of the nodes withthe received label of the FEC information, and the label of the FECinformation is used as an incoming label of the packet forwardingentries of the N-PE (leaf) nodes.

After an N-PE (leaf) node receives the label of the FEC information, theN-PE (leaf) node returns a response message to the N-PE (root) node,notifying that the N-PE (leaf) node has received the label of the FECinformation. If any N-PE (leaf) node does not return a response message,the N-PE (root) node resends the distribution message to that N-PE(leaf) node, to ensure that all the N-PE (leaf) nodes on the RSVP P2MPLSP receive the label of the FEC information.

It should be noted that, an advantage of allocating a unified label ofFEC information to all the N-PE (leaf) nodes on the RSVP P2MP LSP by theN-PE (root) node is that, upon reception of a packet from the upstream,the N-PE (root) needs only to send one packet to an intermediate node,which then replicates and forwards the packet to the downstream N-PE(leaf) nodes. In this way, during packet forwarding, excessive packetreplication is avoided, and bandwidth resources are saved.

410. The network-side root node generates a third mLDP mapping message,where the third mLDP mapping message includes the FEC information and anmLDP label of the network-side root node, and the FEC informationincludes the address of the user-side root node.

Exemplarily, the N-PE (root) node first allocates an mLDP label to theN-PE (root) node itself, and then constructs a third mLDP mappingmessage, where the third mLDP mapping message includes the FECinformation and the mLDP label of the N-PE (root) node, and the FECinformation may include the address of the U-PE (root) node.

After generating the third mLDP mapping message, the N-PE (root) nodemay send the third mLDP mapping message to the upstream U-PE (root).

411. The network-side root node generates a packet forwarding entry ofthe network-side root node according to the mLDP label of thenetwork-side root node, the RSVP P2MP LSP, and the label of the FECinformation.

Exemplarily, the N-PE (root) node associates the mLDP label of the N-PE(root) node with the RSVP P2MP LSP and the label of the FEC informationto generate a packet forwarding entry of the N-PE (root) node, where themLDP label of the N-PE (root) node is set as an incoming label, and anRSVP label of a lower-level node of the N-PE (root) node on the RSVPP2MP LSP is set as an outgoing label, where the RSVP label of the N-PE(leaf) node is allocated when the N-PE (leaf) node establishes the RSVPP2MP LSP to the N-PE (root) node. It should be noted that, sending thethird mLDP mapping message to the upstream U-PE (root) node and creatingthe packet forwarding entry of the local node may be performed at thesame time.

412. The user-side root node receives the third mLDP mapping messagefrom at least one downstream network root node.

Exemplarily, because of point-to-multipoint, the U-PE (root) node mayhave multiple downstream N-PE (root) nodes. Therefore, the third mLDPmapping messages received by the U-PE (root) node may be sent bymultiple N-PE (root) nodes. The third mLDP mapping message sent by eachN-PE (root) node includes the FEC information and an mLDP label value ofthe N-PE (root) that sends the third mLDP mapping message, and the FECinformation includes the address of the U-PE (root) node.

413. The user-side root node generates a packet forwarding entry of theuser-side root node according to the FEC information and the mLDP labelof each network-side root node in the third mLDP mapping message.

In this way, establishment of a whole packet sending path is completed,and mLDP over RSVP P2MP (mLDP P2MP over RSVP P2MP) multicast in anon-VPN scenario is implemented. That is, simple deployment is achievedby using mLDP, and moreover, bandwidth reservation and resource savingare implemented by using RSVP.

In another aspect, at a data level, after the whole mLDP over RSVP P2MPmulticast path is established, as shown in FIG. 5, the method furtherincludes the following:

501. The user-side root node receives a first multicast packet from themulticast source.

502. The user-side root node encapsulates the first multicast packetinto a first MPLS packet by using an mLDP label of the network-side rootnode in the packet forwarding entry of the user-side root node, andsends the first MPLS packet to the network-side root node correspondingto the mLDP label of the network-side root node.

Exemplarily, the U-PE (root) node encapsulates the first multicastpacket into the first MPLS packet by using an outgoing label in theforwarding entry, namely, the mLDP label of the downstream N-PE (root)that sends the mLDP mapping message, and sends the encapsulated firstMPLS packet to the downstream N-PE (root) node corresponding to the mLDPlabel of the N-PE (root) node.

It should be noted that, because the U-PE (root) node may have multipledownstream N-PE (root) nodes, the U-PE (root) node may simultaneouslyforward the first MPLS packet to the multiple downstream N-PE (root)nodes. It should be noted that, the U-PE (root) node sends one packet toeach N-PE (root) node, which then replicates and forwards the packetaccording to the forwarding entry.

503. After receiving the first MPLS packet sent by the user-side rootnode, the network-side root node removes the mLDP label of thenetwork-side root node from the first MPLS packet.

504. The network-side root node replicates a second MPLS packet with themLDP label of the network-side root node removed. The replicated packetsare determined according to the number of outgoing labels in the packetforwarding entry of the network-side root node.

504. The network-side root node encapsulates each replicated MPLS packetinto a third MPLS packet by using the label of the FEC information andan RSVP label of a network-side leaf node in the packet forwarding entryof the network-side root node.

Specifically, the N-PE (root) node may encapsulate the label of the FECinformation as an inner label of the MPLS packet, and encapsulate anRSVP label of an N-PE (leaf) node in the packet forwarding entry of theN-PE (root) node, namely, a downstream N-PE (leaf) node that sends anmLDP mapping message, as an outer label.

505. The network-side root node sends the third MPLS packet to thedownstream network-side leaf node corresponding to the RSVP label.

506. After receiving the third MPLS packet from the upstreamnetwork-side root node, the network-side leaf node removes the RSVPlabel of the network-side leaf node and the label of the FEC informationfrom the third MPLS packet.

507. The network-side leaf node replicates the MPLS packet with the RSVPlabel and the label of the FEC information removed.

Specifically, after removing the RSVP label of the local node from theMPLS packet, the N-PE (leaf) node may find, according to the inner labelof the FEC information and by using the packet forwarding entry of thelocal node, mLDP labels of downstream U-PE (leaf) nodes corresponding tothe label of the FEC information, and then replicate the MPLS packetaccording to these mLDP labels.

508. The network-side leaf node encapsulates the MPLS packet, with thelabel of the FEC information removed, into a fourth MPLS packet by usingan mLDP label in the forwarding entry of the local node.

509. The network-side leaf node sends the fourth MPLS packet to adownstream user-side leaf node corresponding to the mLDP label.

510. After receiving the fourth MPLS packet sent by the upstreamnetwork-side leaf node, the user-side leaf node removes the mLDP labelof the user-side leaf node from the fourth MPLS packet to obtain asecond multicast packet.

511. The user-side leaf node forwards the second multicast packet to areceiver by using the Internet Protocol (IP).

The embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. A network-side leaf nodeacquires an mLDP label of a downstream user-side leaf node and FECinformation from an mLDP mapping message of the downstream user-sideleaf node, then sends an mLDP label of the network-side leaf node andthe FEC information to an upstream network-side root node by using anmLDP mapping message, and generates a forwarding entry; then thenetwork-side root node searches for or establishes an RSVP P2MP LSP,allocates a label value to the received FEC information, and associatesa forwarding entry of each network-side leaf node with the label valueof the FEC information; meanwhile, the network-side root node sends anmLDP label of the network-side root node and the FEC information to anupstream user-side leaf node by using an mLDP mapping message, andassociates the mLDP label of the network-side root node with the RSVPP2MP LSP and the label of the FEC information. In this way, an mLDP overRSVP point-to-multipoint multicast path is established, which isapplicable to P2MP multicast in a non-VPN scenario. Further, duringpacket forwarding, excessive packet replication is avoided, andbandwidth resources are saved.

Still another embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. As shown in FIG. 6, themethod includes the following:

S601. After receiving a multicast join request message sent by adownstream node, a user-side leaf node acquires an address of auser-side root node according to address information of a multicastsource in the multicast join request message (the step is the same asS401; reference may be made to S401, and details are not repeated anyfurther).

S602. The user-side leaf node generates an mLDP mapping message, wherethe mLDP mapping message includes FEC information and a multipoint LabelDistribution Protocol mLDP label of the local node, and the FECinformation includes the address of the user-side root node (the methodis completely the same as S402; reference may be made to S402, anddetails are not repeated any further).

S603. A network-side leaf node receives the mLDP mapping message from atleast one downstream user-side leaf node (the method is completely thesame as S403; reference may be made to S403, and details are notrepeated any further).

S604. The network-side leaf node performs snooping on the mLDP mappingmessage to acquire, from the mLDP mapping message, the FEC informationand the mLDP label of the user-side leaf node to which the mLDP mappingmessage belongs. The FEC includes the address of the user-side rootnode.

Specifically, in a scenario in which neither an N-PE (leaf) node nor anN-PE (root) node supports mLDP, after receiving an mLDP mapping message,the N-PE (leaf) is unable to directly obtain an mLDP label of a U-PE(leaf) node to which an mLDP mapping message belongs and FEC informationfrom the mLDP mapping message. Therefore, it is necessary to performsnooping (Snooping) on the mLDP mapping message to obtain the mLDP labeland FEC information from the message.

S605. The network-side leaf node acquires an address of a network-sideroot node according to the address of the user-side root node in the FECinformation (the method is completely the same as S404; reference may bemade to S404, and details are not repeated any further).

S606. The network-side leaf node sends a first received mLDP mappingmessage to the upstream network-side root node according to the addressof the network-side root node.

Specifically, if FEC information in all mLDP mapping messages sent by atleast one downstream U-PE (leaf) node is the same, message suppressionprocessing is performed on these mLDP mapping messages, that is, the1^(st) message among these messages is transparently transmitted to theupstream N-PE (root) node.

S607. The network-side leaf node generates a packet forwarding entry ofthe network-side root node according to an RSVP label of the local nodeand mLDP labels of all the user-side leaf nodes that send the mLDPmapping messages.

Exemplarily, the RSVP label of the local node may be set as an incominglabel, and the mLDP labels of all the downstream U-PE (leaf) nodes thatsend the mLDP mapping messages may be set as outgoing labels, so as togenerate a packet forwarding entry of the local node.

The RSVP label of the local node is allocated when the local nodeestablishes an RSVP P2MP LSP to the N-PE (root) node. It should be notedthat, sending the 1^(st) mLDP mapping message to the upstream N-PE(root) node and establishing the packet forwarding entry of the localnode may be performed at the same time.

S608. The network-side root node receives the mLDP mapping message,which is sent by the user-side leaf node and forwarded by at least onedownstream network-side leaf node. That is, after the user-side leafnode sends the mLDP mapping message to the network-side leaf node, thenetwork-side leaf node transparently transmits the mLDP mapping messageto the network-side root node.

S609. The network-side root node performs snooping on the received mLDPmapping message to acquire, from the mLDP mapping message, the FECinformation and the mLDP label of the user-side leaf node to which themLDP mapping message belongs (the method is completely the same as S604;reference may be made to S604, and details are not repeated anyfurther).

S610. The network-side root node acquires the RSVP P2MP LSP according tonetwork-side leaf nodes.

Specifically, because the network-side leaf nodes transparently transmitmLDP mapping messages, the network-side root node does not know who thenetwork-side leaf nodes are. Therefore, when transparently transmittingthe mLDP mapping messages, the network-side leaf nodes need to notifythe network-side root node by using a protocol, to indicate that thenetwork-side leaf nodes are network-side leaf nodes. This protocol mayuse a BGP (Border Gateway Protocol, Border Gateway Protocol)-based RSVPP2MP leaf discovery technology, or a distribution protocol may be usedfor implementation. The method for acquiring, by the network-side rootnode, the RSVP P2MP LSP according to the network-side leaf nodes afterthe network-side leaf nodes are discovered is completely the same asthat of S408. Reference may be made to S408, and details are notrepeated any further.

S611. The network-side root node allocates a label to the FECinformation in the mLDP mapping messages, and sends the label of the FECinformation to all the network-side leaf nodes on the RSVP P2MP LSP (themethod is completely the same as S409; reference may be made to S409,and details are not repeated any further).

S612. The network-side root node sends the 1^(st) received mLDP mappingmessage to the upstream user-side root node according to the address ofthe user-side root node.

Specifically, if FEC information in all mLDP mapping messages sent by atleast one downstream N-PE (leaf) node is the same, message suppressionprocessing is performed on these mLDP mapping messages, that is, the1^(st) message among these messages is transparently transmitted to theupstream U-PE (root) node.

S613. The network-side root node generates a packet forwarding entry ofthe network-side root node according to an RSVP label of the local node,mLDP labels of all the network-side leaf nodes that forward the mLDPmapping messages, and the label of the FEC information.

The N-PE (root) node associates the mLDP label in the 1^(st) mLDPmapping message received by the N-PE (root) node with the RSVP P2MP LSPand the label of the FEC information, and generates a packet forwardingentry of the N-PE (root) node, where the mLDP label in the 1^(st) mLDPmapping message received by the N-PE (root) node is set as an incominglabel, and an RSVP label of a lower-level node of the N-PE (root) nodeon the RSVP P2MP LSP is set as an outgoing label, where the RSVP labelof the N-PE (leaf) node is allocated when the N-PE (root) nodeestablishes the RSVP P2MP LSP to the N-PE (leaf) node. It should benoted that, sending the first mLDP mapping message to the upstream U-PE(root) node and establishing the packet forwarding entry of the localnode may be performed at the same time.

S614. The user-side root node receives the mLDP mapping message sent bythe user-side leaf node, from at least one downstream network-side rootnode.

S615. The user-side root node generates a forwarding entry of theuser-side root node according to the FEC information and the mLDP labelof the user-side leaf node to which the mLDP mapping message belongs inthe mLDP mapping message.

In this way, a whole packet sending path is established. In a case inwhich a network-side node (N-PE) does not support mLDP, mLDP over RSVPP2MP (mLDP P2MP over RSVP P2MP) multicast in a non-VPN scenario isimplemented by using a Snooping function. That is, simple deployment isachieved by using mLDP, and bandwidth reservation and resource savingare implemented by using RSVP. In addition, message suppressionprocessing is performed on mLDP mapping messages that include the sameFEC information, and only the 1^(st) mLDP mapping message is forwardedto the upstream, which further saves bandwidth and reduces processingload of the node.

In another aspect, at a data level, after the whole mLDP over RSVP P2MPmulticast path is established, as shown in FIG. 7, the method furtherincludes the following:

S701. The user-side root node receives a multicast packet from themulticast source.

S702. The user-side root node encapsulates the multicast packet into anMPLS packet by using the mLDP label of the user-side leaf node in theforwarding entry of the user-side root node, and sends the MPLS packetto the downstream network-side root node corresponding to the mLDP labelof the user-side leaf node.

Specifically, because the N-PE (root) node does not support mLDP, theN-PE (root) node does not allocate an mLDP label to the N-PE (root) nodeitself, but transparently transmits, to the upstream user-side rootnode, the 1^(st) mLDP mapping message sent by the downstream user-sideleaf node. Therefore, when encapsulating the multicast packet, theuser-side root node encapsulates the multicast packet by using the mLDPlabel in the received mLDP mapping message.

S703. After receiving the MPLS packet sent by the user-side root node,the network-side root node removes the mLDP label of the user-side leafnode from the MPLS packet.

S704. The network-side root node replicates the MPLS packet with themLDP label removed. The number of replicated packets is determinedaccording to the number of outgoing labels in the packet forwardingentry of the network-side root node.

S705. The network-side root node encapsulates each replicated MPLSpacket by using the label of the FEC information and the RSVP label ofthe network-side leaf node in the packet forwarding entry of thenetwork-side root node (the method is completely the same as S504;reference may be made to S504, and details are not repeated anyfurther).

S706. The network-side root node sends the encapsulated MPLS packet tothe downstream network-side leaf node corresponding to the RSVP label.

S707. After receiving the MPLS packet from the upstream network-sideroot node, the network-side leaf node removes the RSVP label of thelocal node and the label of the FEC information from the MPLS packet.

S708. The network-side leaf node replicates the MPLS packet with theRSVP label and the label of the FEC information removed (the method iscompletely the same as S507; reference may be made to S507, and detailsare not repeated any further).

S709. The network-side leaf node encapsulates, by using the mLDP labelin the forwarding entry of the node, the MPLS packet with the label ofthe FEC information removed.

S710. The network-side leaf node sends the encapsulated MPLS packet tothe downstream user-side leaf node corresponding to the mLDP label.

S711. After receiving the MPLS packet sent by the upstream network-sideleaf node, the user-side leaf node removes the mLDP label of theuser-side leaf node from the MPLS packet to obtain a multicast packet.

S712. The user-side leaf node forwards the multicast packet to areceiver by using the Internet Protocol IP.

This embodiment further provides a failover method for a part of linksof an mLDP P2MP LSP. A specific implementation manner may be as follows:

The mLDP protocol is used for processing between an intermediate node P(leaf) node and a PE (root) node. The PE (root) node and the P (leaf)node may be designated by manual configuration, or may be acquired bycalculation according to network-wide routing information, mLDP FECinformation, and information about which nodes in the network supportRSVP P2MP.

After the PE (root) node and the P (leaf) node that supports RSVP P2MPare selected, a backup RSVP P2MP LSP is established, and an inner label,namely, a label of FEC information, is allocated. For a specificimplementation manner, reference may be made to S409, and details arenot repeated any further.

Then when establishing an mLDP P2MP LSP, the PE (root) node needs toassociate the label of the FEC information with the mLDP P2MP LSP and abackup RSVP P2MP LSP.

FIG. 8 shows an mLDP P2MP LSP, where a dotted line represents a backupRSVP P2MP LSP. When a failure occurs, a packet may be switched from themLDP P2MP LSP to the backup RSVP P2MP LSP. In this way, a process ofre-convergence of a routing protocol is avoided, a switching speed ishigh, and service interruption can be prevented.

The embodiment of the present invention provides a method forimplementing point-to-multipoint multicast. First, a network-side leafnode acquires an mLDP label of a downstream user-side leaf node and FECinformation by performing snooping on an mLDP mapping message of thedownstream user-side leaf node, then transparently transmits the 1^(st)received mLDP mapping message to an upstream network-side root node, andgenerates a forwarding entry; then the network-side root node searchesfor or establishes an RSVP P2MP LSP, allocates a label value to thereceived FEC information, and associates a forwarding entry of eachnetwork-side leaf node with the label value of the FEC information;meanwhile, the network-side root node transparently transmits the 1^(st)received mLDP mapping message to an upstream user-side leaf node, andassociates the mLDP label in the mLDP mapping message with the RSVP P2MPLSP and the label of the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Because the node can acquireFEC information and an mLDP label of a downstream node from an mLDPmapping message by snooping, it is not necessary for each node tocompletely support mLDP, so that deployment can also be implemented whena node does not support mLDP. Further, during packet forwarding,excessive packet replication can be avoided, and bandwidth resources canbe saved. In addition, message suppression processing is performed onmLDP mapping messages that include the same FEC information, whichfurther saves bandwidth and reduces processing load of the node.

The present invention provides a network node 01. As shown in FIG. 9,the network node 01 includes:

a first receiving unit 011, configured to receive an mLDP mappingmessage from at least one downstream node, where each mLDP mappingmessage includes forwarding equivalence class FEC information and anmLDP label of a node to which the mLDP mapping message belongs, and sendeach mLDP mapping message to a first label allocating unit 013 and afirst entry creating unit 014;

a first path acquiring unit 012, configured to acquire an RSVP P2MP LSPaccording to the downstream nodes that send the mLDP mapping messages,and send information about the RSVP P2MP LSP to the first labelallocating unit 013 and the first entry creating unit 014;

the first label allocating unit 013, configured to receive each mLDPmapping message from the first receiving unit 011, receive theinformation about the RSVP P2MP LSP from the first path acquiring unit012, allocate a label to the FEC information, and send the label of theFEC information to all the nodes that are on the RSVP P2MP LSP and sendthe mLDP mapping messages;

the first entry creating unit 014, configured to receive each mLDPmapping message from the first receiving unit 011, receive theinformation about the RSVP P2MP LSP from the first path acquiring unit012, and generate a packet forwarding entry of the local node accordingto an mLDP label of the local node, the RSVP P2MP LSP, and the label ofthe FEC information; and

a first sending unit 015, configured to send a new mLDP mapping messageto an upstream node, where the new mLDP mapping message includes the FECinformation and the mLDP label of the local node, and the FECinformation includes an address of a user-side root node.

Further, the first path acquiring unit 012 may be specificallyconfigured to:

search for an existing RSVP P2MP LSP according to the downstream nodesthat send the mLDP mapping messages; or

establish the RSVP P2MP LSP according to the downstream nodes that sendthe mLDP mapping messages,

where the RSVP P2MP LSP includes all the downstream nodes that send themLDP mapping messages.

Still further, the first label allocating unit 013 may be specificallyconfigured to:

send a distribution message that includes the FEC information and thelabel of the FEC information to an intermediate node, so that theintermediate node sends, after replicating the distribution message, thedistribution message to all the nodes that are on the RSVP P2MP LSP andsend the mLDP mapping messages; or

after connections are established to all the nodes that are on the RSVPP2MP LSP and send the mLDP mapping messages, send a distribution messagedirectly to all the nodes that are on the RSVP P2MP LSP and send themLDP mapping messages, so that all the nodes that send the mLDP mappingmessages use the label of the FEC information as an incoming label ofpacket forwarding entries of the nodes.

Still further, the first entry creating unit 014 is specificallyconfigured to:

associate the mLDP label of the local node with the RSVP P2MP LSP andthe label of the FEC information, and generate the packet forwardingentry of the local node, where the mLDP label of the local node is setas an incoming label, and an RSVP label of a downstream node that sendsthe mLDP mapping message is set as an outgoing label, where the RSVPlabel of the downstream node that sends the mLDP mapping message isallocated when the RSVP P2MP LSP is established.

Still further, the first receiving unit 011 is configured to receive amulti-protocol label switching packet from an upstream node, where themulti-protocol label switching packet is encapsulated by the user-sideroot node by using an mLDP label of the local node.

As shown in FIG. 10, the network node 01 may further include:

a first label processing unit 016, configured to remove the mLDP labelof the local node from the multi-protocol label switching packet, andsend the multi-protocol label switching packet with the mLDP labelremoved to a first packet replicating unit 017; and

the first packet replicating unit 017, configured to receive, from thefirst label processing unit 016, the multi-protocol label switchingpacket with the mLDP label removed, replicate the multi-protocol labelswitching packet with the mLDP label removed, where the number ofreplicated multi-protocol label switching packets is equal to the numberof outgoing labels in the packet forwarding entry of the local node, andsend the replicated multi-protocol label switching packets to the firstlabel processing unit 016, where:

the first label processing unit 016 is further configured to receive thereplicated multi-protocol label switching packets from the first packetreplicating unit 017, encapsulate the replicated multi-protocol labelswitching packet by using the label of the FEC information and an RSVPlabel of a downstream node that sends an mLDP mapping message, where thelabel of the FEC information is used as an inner label, and the RSVPlabel of the downstream node that sends the mLDP mapping message is usedas an outer label, and then send, by using the first sending unit 015,the multi-protocol label switching packet to the downstream nodecorresponding to the RSVP label of the downstream node that sends themLDP mapping message.

The embodiment of the present invention provides a network node. Afterreceiving an mLDP mapping message sent by a network-side leaf node, thenetwork node acquires an RSVP P2MP LSP, allocates a label value toreceived FEC information, and associates a forwarding entry of eachnetwork-side leaf node with the label value of the FEC information;meanwhile, the network-side root node sends an mLDP label of thenetwork-side root node and the FEC information to an upstream user-sideleaf node by using an mLDP mapping message, and associates the mLDPlabel of the network-side root node with the RSVP P2MP LSP and the labelof the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Further, during packetforwarding, excessive packet replication is avoided, and bandwidthresources are saved.

The present invention provides a network node 02. As shown in FIG. 11,the network node 02 includes:

a second receiving unit 021, configured to receive an mLDP mappingmessage, which is sent by a user-side leaf node and forwarded by atleast one downstream node, and send the received mLDP mapping message toa message snooping unit 022;

the message snooping unit 022, configured to perform snooping on thereceived mLDP mapping message to acquire, from the mLDP mapping message,FEC information and an mLDP label of the user-side leaf node to whichthe mLDP mapping message belongs, and send the message undergoing thesnooping to a second label allocating unit 024 and a second entrycreating unit 025;

a second path acquiring unit 023, configured to acquire a ResourceReservation Protocol point-to-multipoint path RSVP P2MP LSP;

the second label allocating unit 024, configured to receive, from thesecond receiving unit 021, the message undergoing the snooping, allocatea label to the FEC information, and send the label of the FECinformation to all the nodes that are on the RSVP P2MP LSP and forwardthe mLDP mapping messages;

the second entry creating unit 025, configured to receive, from thesecond receiving unit 021, the message undergoing the snooping, andaccording to an mLDP label in the 1^(st) mLDP mapping message receivedby the local node, the RSVP P2MP LSP, and the label of the FECinformation, generate a packet forwarding entry of the local node; and

a second sending unit 026, configured to forward the 1^(st) mLDP mappingmessage among received mLDP mapping messages that belong to the same FECinformation, to an upstream node.

Further, the second entry creating unit 025 may be specificallyconfigured to:

associate the mLDP label in the 1^(st) mLDP mapping message received bythe local node with the RSVP P2MP LSP and the label of the FECinformation, and generate the packet forwarding entry of thenetwork-side root node, where the mLDP label in the 1^(st) mLDP mappingmessage received by the local node is set as an incoming label, and anRSVP label of a downstream node that forwards the mLDP mapping messageis set as an outgoing label, where the RSVP label of the lower-levelnode of the local node is allocated when the RSVP P2MP LSP isestablished.

Still further, the second receiving unit 021 is further configured toreceive a multi-protocol label switching packet from an upstream node,where the multi-protocol label switching packet is encapsulated by auser-side root node by using the mLDP label of the user-side leaf node.

As shown in FIG. 12, the network node 02 may further include:

a second label processing unit 027, configured to remove the mLDP labelof the user-side leaf node from the multi-protocol label switchingpacket, and send the multi-protocol label switching packet with the mLDPlabel removed, to a second packet replicating unit 028; and

the second packet replicating unit 028, configured to receive, from thesecond label processing unit 027, the multi-protocol label switchingpacket with the mLDP label removed, and replicate the multi-protocollabel switching packet with the mLDP label removed, where the number ofreplicated multi-protocol label switching packets is equal to the numberof outgoing labels in the packet forwarding entry of the network-sideroot node.

The second label processing unit 027 is further configured to receivethe replicated multi-protocol label switching packets from the secondpacket replicating unit 028, encapsulate the replicated multi-protocollabel switching packets by using the label of the FEC information andthe RSVP label of the downstream node that forwards the mLDP mappingmessage, where the label of the FEC information is used as an innerlabel, and the RSVP label of the downstream node that forwards the mLDPmapping message is used as an outer label, and send, by using the secondsending unit 026, the multi-protocol label switching packet to thedownstream node corresponding to the RSVP label of the downstream nodethat forwards the mLDP mapping message.

The embodiment of the present invention provides a network node. First,the network node acquires an mLDP label of a downstream user-side leafnode and FEC information by performing snooping on an mLDP mappingmessage of a downstream network-side leaf node; then the network-sideroot node searches for or establishes an RSVP P2MP LSP, allocates alabel value to the received FEC information, and associates a forwardingentry of each network-side leaf node with the label value of the FECinformation; meanwhile, the network-side root node transparentlytransmits the 1^(st) received mLDP mapping message to an upstream node,and associates an mLDP label in the mLDP mapping message with the RSVPP2MP LSP and the label of the FEC information. In this way, an mLDP overRSVP point-to-multipoint multicast path is established, which isapplicable to P2MP multicast in a non-VPN scenario. Because the node canacquire FEC information and an mLDP label of a downstream node from anmLDP mapping message by snooping, it is not necessary for each node tocompletely support mLDP, so that deployment can also be implemented whena node does not support mLDP. Further, during packet forwarding,excessive packet replication can be avoided, and bandwidth resources canbe saved. In addition, message suppression processing is performed onmLDP mapping messages that include the same FEC information, whichfurther saves bandwidth and reduces processing load of the node.

The present invention provides a network node 03. As shown in FIG. 13,the network node 03 includes:

a third receiving unit 031, configured to receive a distribution messagethat includes FEC information and a label of the FEC information from anupstream node, and send the distribution message to a third labelprocessing unit 033;

a third sending unit 032, configured to send a response message to theupstream node that sends the distribution message; and

the third label processing unit 033, configured to receive thedistribution message from the third receiving unit 031, and use thelabel of the FEC information as an incoming label of a packet forwardingentry of the local node.

Further, the third receiving unit 031 may be specifically configured to:

receive, from an intermediate node, the distribution message sent by thenetwork-side root node; or

after a connection is established to the network-side root node on anRSVP P2MP LSP, receive the distribution message directly from thenetwork-side root node.

Still further, the third receiving unit 031 is further configured toreceive a multi-protocol label switching packet from the upstreamnetwork-side root node; and

the third label processing unit 033 is further configured to remove anRSVP label of the local node and the label of the FEC information fromthe multi-protocol label switching packet, where the RSVP label of thelocal node is allocated when the local node establishes the RSVP P2MPLSP to the network-side root node.

Still further, as shown in FIG. 14, the network node 03 furtherincludes:

a third packet replicating unit 034, configured to replicate themulti-protocol label switching packet with the RSVP label and the labelof the FEC information removed, where the number of replicatedmulti-protocol label switching packets is determined according to thenumber of mLDP labels of downstream nodes corresponding to the label ofthe FEC information, and send the replicated multi-protocol labelswitching packets to the third label processing unit 033.

The third label processing unit 033 is further configured to receive thereplicated multi-protocol label switching packets from the third packetreplicating unit 034, encapsulate the replicated multi-protocol labelswitching packet by using an mLDP label in an mLDP mapping message sentby a downstream node, and send, by using the third sending unit 032, themulti-protocol label switching packet to the downstream nodecorresponding to the mLDP label of the downstream node.

The embodiment of the present invention provides a network node, whichis configured to receive a distribution message sent by an upstreamnetwork-side root node, to acquire a label of FEC information, so thatan mLDP label of the local node is associated with an RSVP P2MP LSP andthe label of the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Because the node can acquireFEC information and an mLDP label of a downstream node from an mLDPmapping message by snooping, it is not necessary for each node tocompletely support mLDP, so that deployment can also be implemented whena node does not support mLDP. Further, during packet forwarding,excessive packet replication can be avoided, and bandwidth resources canbe saved.

An embodiment of the present invention further provides an edge device04, which includes a bus 041 and a memory 042, and as shown in FIG. 15,further includes:

a first receiver 043, configured to receive an mLDP mapping message fromat least one downstream node, where each mLDP mapping message includesforwarding equivalence class FEC information and an mLDP label of a nodeto which the mLDP mapping message belongs;

a first processor 044, configured to acquire a Resource ReservationProtocol point-to-multipoint path RSVP P2MP LSP according to thedownstream nodes that send the mLDP mapping messages;

the first processor 044, further configured to allocate a label to theFEC information, and send the label of the FEC information to all thenodes that send the mLDP mapping message and are on the RSVP P2MP LSP;where:

the first processor 044 is further configured to generate a packetforwarding entry of the local node according to an mLDP label of thelocal node, the RSVP P2MP LSP, and the label of the FEC information; and

a first transmitter 045, configured to send a new mLDP mapping messageto an upstream node, where the new mLDP mapping message includes the FECinformation and the mLDP label of the local node, and the FECinformation includes an address of a user-side root node.

Further, the first processor 044 may be specifically configured to:

search for an existing RSVP P2MP LSP according to the downstream nodesthat send the mLDP mapping messages; or

establish the RSVP P2MP LSP according to the downstream nodes that sendthe mLDP mapping messages;

where the RSVP P2MP LSP includes all the downstream nodes that send themLDP mapping messages.

Still further, the first processor 044 may be specifically configuredto:

send a distribution message that includes the FEC information and thelabel of the FEC information to an intermediate node, so that theintermediate node sends, after replicating the distribution message, thedistribution message to all the nodes that are on the RSVP P2MP LSP andsend the mLDP mapping messages; or

after connections are established to all the nodes that are on the RSVPP2MP LSP and send the mLDP mapping messages, send a distribution messagedirectly to all the nodes that are on the RSVP P2MP LSP and send themLDP mapping messages, so that all the nodes that send the mLDP mappingmessages use the label of the FEC information as an incoming label ofpacket forwarding entries of the nodes.

Still further, the first processor 044 may be specifically configuredto:

associate the mLDP label of the local node with the RSVP P2MP LSP andthe label of the FEC information, and generate the packet forwardingentry of the local node, where the mLDP label of the local node is setas an incoming label, and an RSVP label of a downstream node that sendsthe mLDP mapping message is set as an outgoing label, where the RSVPlabel of the downstream node that sends the mLDP mapping message isallocated when the RSVP P2MP LSP is established.

Still further, the first receiver 043 may be configured to receive amulti-protocol label switching packet from an upstream node, where themulti-protocol label switching packet is encapsulated by the user-sideroot node by using an mLDP label of the local node.

The first processor 044 may be further configured to:

remove the mLDP label of the local node from the multi-protocol labelswitching packet;

replicate the multi-protocol label switching packet with the mLDP labelremoved, where the number of replicated multi-protocol label switchingpackets is equal to the number of outgoing labels in the packetforwarding entry of the local node; and

encapsulate the replicated multi-protocol label switching packet byusing the label of the FEC information and an RSVP label of a downstreamnode that sends an mLDP mapping message, where the label of the FECinformation is used as an inner label, and the RSVP label of thedownstream node that sends the mLDP mapping message is used as an outerlabel, and send, by using the first transmitter 045, the multi-protocollabel switching packet to the downstream node corresponding to the RSVPlabel of the downstream node that sends the mLDP mapping message.

The embodiment of the present invention provides an edge device. Afterreceiving an mLDP mapping message sent by a network-side leaf node, theedge device acquires an RSVP P2MP LSP, allocates a label value toreceived FEC information, and associates a forwarding entry of eachnetwork-side leaf node with the label value of the FEC information;meanwhile, the network-side root node sends an mLDP label of thenetwork-side root node and the FEC information to an upstream user-sideleaf node by using an mLDP mapping message, and associates the mLDPlabel of the network-side root node with the RSVP P2MP LSP and the labelof the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Further, during packetforwarding, excessive packet replication can be avoided, and bandwidthresources can be saved.

An embodiment of the present invention further provides an edge device05, which includes a bus 051 and a memory 052, and as shown in FIG. 16,further includes:

a second receiver 053, configured to receive an mLDP mapping message,which is sent by a user-side leaf node and forwarded by at least onedownstream node;

a second processor 054, configured to perform snooping on the receivedmLDP mapping message to acquire, from the mLDP mapping message, FECinformation and an mLDP label of the user-side leaf node to which themLDP mapping message belongs; where

the second processor 054 is further configured to acquire a ResourceReservation Protocol point-to-multipoint path RSVP P2MP LSP;

the second processor 054 is further configured to allocate a label tothe FEC information, and send the label of the FEC information to allthe nodes that forward the mLDP mapping message and are on the RSVP P2MPLSP;

the second processor 054 is further configured to generate a packetforwarding entry of the local node according to an mLDP label in the1^(st) mLDP mapping message received by the local node, the RSVP P2MPLSP, and the label of the FEC information; and

a second transmitter 055, configured to forward the 1^(st) mLDP mappingmessage among received mLDP mapping messages that belong to the same FECinformation, to an upstream node.

Further, the second processor 054 may be specifically configured to:

associate the mLDP label in the 1^(st) mLDP mapping message received bythe local node with the RSVP P2MP LSP and the label of the FECinformation, and generate the packet forwarding entry of thenetwork-side root node, where the mLDP label in the 1^(st) mLDP mappingmessage received by the local node is set as an incoming label, and anRSVP label of a downstream node that forwards the mLDP mapping messageis set as an outgoing label, where the RSVP label of the downstream nodethat forwards the mLDP mapping message is allocated when the RSVP P2MPLSP is established.

Still further, the second receiver 053 is configured to receive amulti-protocol label switching packet from an upstream node, where themulti-protocol label switching packet is encapsulated by a user-sideroot node by using the mLDP label of the user-side leaf node.

The second processor 054 may be further configured to:

remove the mLDP label of the user-side leaf node from the multi-protocollabel switching packet;

replicate the multi-protocol label switching packet with the mLDP labelremoved, where the number of replicated multi-protocol label switchingpackets is equal to the number of outgoing labels in the packetforwarding entry of the network-side root node; and

encapsulate the replicated multi-protocol label switching packet byusing the label of the FEC information and the RSVP label of thedownstream node that forwards the mLDP mapping message, where the labelof the FEC information is used as an inner label, and the RSVP label ofthe downstream node that forwards the mLDP mapping message is used as anouter label, and send, by using the second transmitter 055, themulti-protocol label switching packet to the downstream nodecorresponding to the RSVP label of the downstream node that forwards themLDP mapping message.

The embodiment of the present invention provides an edge device. First,the edge device acquires an mLDP label of a downstream user-side leafnode and FEC information by performing snooping on an mLDP mappingmessage of a downstream network-side leaf node; then the network-sideroot node searches for or establishes an RSVP P2MP LSP, allocates alabel value to the received FEC information, and associates a forwardingentry of each network-side leaf node with the label value of the FECinformation; meanwhile, the network-side root node transparentlytransmits the 1^(st) received mLDP mapping message to an upstream node,and associates an mLDP label in the mLDP mapping message with the RSVPP2MP LSP and the label of the FEC information. In this way, an mLDP overRSVP point-to-multipoint multicast path is established, which isapplicable to P2MP multicast in a non-VPN scenario. Because the node canacquire FEC information and an mLDP label of a downstream node from anmLDP mapping message by snooping, it is not necessary for each node tocompletely support mLDP, so that deployment can also be implemented whena node does not support mLDP. Further, during packet forwarding,excessive packet replication can be avoided, and bandwidth resources canbe saved. In addition, message suppression processing is performed onmLDP mapping messages that include the same FEC information, whichfurther saves bandwidth and reduces processing load of the node.

An embodiment of the present invention further provides an edge device06, which includes a bus 061 and a memory 062, and as shown in FIG. 17,further includes:

a third receiver 063, configured to receive a distribution message thatincludes FEC information and a label of the FEC information from anupstream node;

a third transmitter 064, configured to send a response message to theupstream node that sends the distribution message; and

a third processor 065, configured to use the label of the FECinformation as an incoming label of a packet forwarding entry of thelocal node.

Further, the third transmitter 064 may be specifically configured to:

receive, from an intermediate node, the distribution message sent by thenetwork-side root node; or

after a connection is established to the network-side root node on anRSVP P2MP LSP, receive the distribution message directly from thenetwork-side root node.

Still further, the third receiver 063 receives a multi-protocol labelswitching packet from the upstream network-side root node; and

the third processor 065 may be further configured to:

remove an RSVP label of the local node and the label of the FECinformation from the multi-protocol label switching packet, where theRSVP label of the local node is allocated when the RSVP P2MP LSP isestablished;

replicate the multi-protocol label switching packet with the RSVP labeland the label of the FEC information removed, where the number ofreplicated multi-protocol label switching packets is determinedaccording to the number of mLDP labels of downstream nodes correspondingto the label of the FEC information; and

encapsulate the replicated multi-protocol label switching packet byusing an mLDP label in an mLDP mapping message sent by a downstreamnode, and send the multi-protocol label switching packet to thedownstream node corresponding to the mLDP label of the downstream node.

The embodiment of the present invention provides an edge device, whichis configured to receive a distribution message sent by an upstreamnetwork-side root node, to acquire a label of FEC information, so thatan mLDP label of the local node is associated with an RSVP P2MP LSP andthe label of the FEC information. In this way, an mLDP over RSVPpoint-to-multipoint multicast path is established, which is applicableto P2MP multicast in a non-VPN scenario. Because the node can acquireFEC information and an mLDP label of a downstream node from an mLDPmapping message by snooping, it is not necessary for each node tocompletely support mLDP, so that deployment can also be implemented whena node does not support mLDP. Further, during packet forwarding,excessive packet replication can be avoided, and bandwidth resources canbe saved.

An embodiment of the present invention further provides a communicationssystem 1, which includes receivers 07, a multicast source 08, user-sideleaf nodes 09, and a user-side root node 10, and as shown in FIG. 18,further includes:

a network node 01 and network nodes 03 provided in the foregoingembodiments.

The embodiment of the present invention provides a communicationssystem. A network-side leaf node acquires an mLDP label of a downstreamuser-side leaf node and FEC information from an mLDP mapping message ofthe downstream user-side leaf node, then sends an mLDP label of thenetwork-side leaf node and the FEC information to an upstreamnetwork-side root node by using an mLDP mapping message, and generates aforwarding entry; then the network-side root node acquires an RSVP P2MPLSP, allocates a label value to the received FEC information, andassociates a forwarding entry of each network-side leaf node with thelabel value of the FEC information; meanwhile, the network-side rootnode sends an mLDP label of the network-side root node and the FECinformation to an upstream user-side leaf node by using an mLDP mappingmessage, and associates the mLDP label of the network-side root nodewith the RSVP P2MP LSP and the label of the FEC information. In thisway, an mLDP over RSVP point-to-multipoint multicast path isestablished, which is applicable to P2MP multicast in a non-VPNscenario. Further, during packet forwarding, excessive packetreplication is avoided, and bandwidth resources are saved.

An embodiment of the present invention further provides a communicationsystem 2, which includes receivers 07, a multicast source 08, user-sideleaf nodes 09, and a user-side root node 10, and as shown in FIG. 19,further includes:

a network node 02 and network nodes 03 provided in the foregoingembodiments.

The embodiment of the present invention provides a communicationssystem. First, a network-side leaf node acquires an mLDP label of adownstream user-side leaf node and FEC information by performingsnooping on an mLDP mapping message of the downstream user-side leafnode, then transparently transmits the 1^(st) received mLDP mappingmessage to an upstream network-side root node, and generates aforwarding entry; then the network-side root node acquires an RSVP P2MPLSP, allocates a label value to the received FEC information, andassociates a forwarding entry of each network-side leaf node with thelabel value of the FEC information; meanwhile, the network-side rootnode transparently transmits the 1^(st) received mLDP mapping message toan upstream user-side leaf node, and associates the mLDP label in themLDP mapping message with the RSVP P2MP LSP and the label of the FECinformation. In this way, an mLDP over RSVP point-to-multipointmulticast path is established, which is applicable to P2MP multicast ina non-VPN scenario. Because the node can acquire FEC information and anmLDP label of a downstream node from an mLDP mapping message bysnooping, it is not necessary for each node to completely support mLDP,so that deployment can also be implemented when a node does not supportmLDP. Further, during packet forwarding, excessive packet replicationcan be avoided, and bandwidth resources can be saved. In addition,message suppression processing is performed on mLDP mapping messagesthat include the same FEC information, which further saves bandwidth andreduces processing load of the node.

In the several embodiments provided in the present application, itshould be understood that the disclosed system, apparatus, and methodmay be implemented in other manners. For example, the describedapparatus embodiment is merely exemplary. For example, the unit divisionis merely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcommunication connections may be implemented through some interfaces.The indirect couplings or communication connections between theapparatuses or units may be implemented in electronic, mechanical, orother forms.

The units may or may not be physically separate, may or may not bephysical units, may be located in one position, or may be distributed ona plurality of network units. A part or all of the units may be selectedaccording to actual needs to achieve the objectives of the solutions ofthe embodiments.

In addition, functional units in the embodiments of the presentinvention may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit. The integrated unit may be implemented in a form ofhardware, or may be implemented in a form of a software functional unit.

When the foregoing integrated unit is implemented in a form of asoftware functional unit, the integrated unit may be stored in acomputer-readable storage medium. The software functional unit is storedin a storage medium and includes several instructions for instructing acomputer device (which may be a personal computer, a server, or anetwork device) to perform a part of the steps of the methods describedin the embodiments of the present invention. The foregoing storagemedium includes: any medium that can store program code, such as a USBflash drive, a removable hard disk, a read-only memory (Read-OnlyMemory, ROM for short), a random access memory (Random Access Memory,RAM for short), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementation manners ofthe present invention, but are not intended to limit the protectionscope of the present invention. Any variation or replacement readilyfigured out by a person skilled in the art within the technical scopedisclosed in the present invention shall fall within the protectionscope of the present invention. Therefore, the protection scope of thepresent invention shall be subject to the protection scope of theclaims.

What is claimed is:
 1. A method for implementing point-to-multipointmulticast, wherein a multicast source communicates with multicastreceivers by using a network running multicast Label DistributionProtocol (mLDP) and a network running Reservation Protocol (RSVP),wherein the network running RSVP comprises a network-side root node andnetwork-side leaf nodes, the network-side root node is a Provider Edge(PE) node that is in the network running RSVP and is oriented to themulticast source, the network-side leaf nodes are PE nodes that are inthe network running RSVP and are oriented to the multicast receivers,the network-side root node communicates with the multicast source byusing the network running mLDP, and the network-side leaf nodescommunicate with the multicast receivers by using the network runningmLDP, and wherein the network running mLDP comprises a user-side rootnode and user-side leaf nodes, the user-side root node is a PE node thatis in the network running mLDP and is oriented to the multicast source,and the user-side leaf nodes are PE nodes that are in the networkrunning mLDP and are oriented to the multicast receivers, and whereinthe method comprises: receiving, by the network-side root node, an mLDPmapping message from at least one downstream network-side leaf node,wherein each mLDP mapping message comprises forwarding equivalence class(FEC) information and an mLDP label of a network-side leaf node thatsends the mLDP mapping message, and the FEC information comprises anaddress of the user-side root node; acquiring a Resource ReservationProtocol point-to-multipoint path (RSVP P2MP LSP) according to thenetwork-side leaf node that sends the mLDP mapping message; allocating alabel to the FEC information, and sending the label of the FECinformation to all the nodes that are on the RSVP P2MP LSP and that sendthe mLDP mapping messages; generating a packet forwarding entry of thenetwork-side root node according to an mLDP label of the network-sideroot node, the RSVP P2MP LSP, and the label of the FEC information; andsending a new mLDP mapping message to an upstream node, wherein the newmLDP mapping message comprises the FEC information and the mLDP label ofthe network-side root node, and the FEC information comprises theaddress of the user-side root node.
 2. The method according to claim 1,wherein the acquiring a Resource Reservation Protocolpoint-to-multipoint path (RSVP P2MP LSP) according to the network-sideleaf node that sends the mLDP mapping message comprises at least one of:searching for an existing RSVP P2MP LSP according to the network-sideleaf node that sends the mLDP mapping message; or establishing the RSVPP2MP LSP according to the network-side leaf node that sends the mLDPmapping message; wherein the RSVP P2MP LSP comprises all the downstreamnetwork-side leaf nodes that send the mLDP mapping messages.
 3. Themethod according to claim 1, wherein the allocating a label of FECinformation to the FEC information, and sending the label of the FECinformation to all the nodes that are on the RSVP P2MP LSP and that sendthe mLDP mapping messages comprises: sending a distribution message thatcomprises the FEC information and the label of the FEC information to anintermediate node, so that the intermediate node sends, afterreplicating the distribution message, the distribution message to allthe nodes that are on the RSVP P2MP LSP and that send the mLDP mappingmessages; or after connections are established to all the nodes that areon the RSVP P2MP LSP and sending the mLDP mapping messages, sending adistribution message directly to all the nodes that are on the RSVP P2MPLSP and that send the mLDP mapping messages, so that all the nodes thatsend the mLDP mapping messages use the label of the FEC information asan incoming label of packet forwarding entries of the nodes.
 4. Themethod according to claim 1, wherein the generating a packet forwardingentry of the network-side root node according to an mLDP label of thenetwork-side root node, the RSVP P2MP LSP, and the label of the FECinformation comprises: associating the mLDP label of the network-sideroot node with the RSVP P2MP LSP and the label of the FEC information;and generating the packet forwarding entry of the network-side rootnode, wherein the mLDP label of the network-side root node is set as anincoming label, and an RSVP label of a downstream node that sends themLDP mapping message is set as an outgoing label, and wherein the RSVPlabel of the downstream node that sends the mLDP mapping message isallocated when the RSVP P2MP LSP is established.
 5. The method accordingto claim 1, wherein the method further comprises: receiving amulti-protocol label switching packet from an upstream node, wherein themulti-protocol label switching packet is encapsulated by the user-sideroot node by using an mLDP label of the user-side root node; removingthe mLDP label of the user-side root node from the multi-protocol labelswitching packet; replicating the multi-protocol label switching packetwith the mLDP label removed, wherein the number of replicatedmulti-protocol label switching packets is equal to the number ofoutgoing labels in the packet forwarding entry of the network-side rootnode; and encapsulating the replicated multi-protocol label switchingpacket by using the label of the FEC information and an RSVP label of adownstream node that sends an mLDP mapping message, wherein the label ofthe FEC information is used as an inner label, and the RSVP label of thedownstream node that sends the mLDP mapping message is used as an outerlabel, and sending the encapsulated multi-protocol label switchingpacket to the downstream node corresponding to the RSVP label of thedownstream node that sends the mLDP mapping message.
 6. A method forimplementing point-to-multipoint multicast, wherein a multicast sourcecommunicates with multicast receivers by using a network running mLDPand a network running RSVP, wherein the network running RSVP comprises anetwork-side root node and network-side leaf nodes, wherein thenetwork-side root node is a PE node that is in the network running RSVPand is oriented to the multicast source, wherein the network-side leafnodes are PE nodes that are in the network running RSVP and are orientedto the multicast receivers, wherein the network-side root nodecommunicates with the multicast source by using the network runningmLDP, wherein the network-side leaf nodes communicate with the multicastreceivers by using the network running mLDP, wherein the network runningmLDP comprises a user-side root node and user-side leaf nodes, whereinthe user-side root node is a PE node that is in the network running mLDPand is oriented to the multicast source, and wherein the user-side leafnodes are PE nodes that are in the network running mLDP and are orientedto the multicast receivers, the method comprising: receiving, by thenetwork-side root node, an mLDP mapping message, which is sent by auser-side leaf node and forwarded by at least one network-side leafnode, wherein the mLDP mapping message comprises FEC information and anmLDP label of the user-side leaf node that sends the mLDP mappingmessage; acquiring, from the mLDP mapping message, the FEC informationand the mLDP label of the user-side leaf node that sends the mLDPmapping message; acquiring a Resource Reservation Protocolpoint-to-multipoint path (RSVP P2MP LSP) according to the user-side leafnode that sends the mLDP mapping message; allocating a label of FECinformation to the FEC information, and sending the label of the FECinformation to all the network-side leaf nodes that are on the RSVP P2MPLSP and forward the mLDP mapping message; generating a packet forwardingentry of the network-side root node according to an mLDP label in afirst mLDP mapping message received by the network-side root node, theRSVP P2MP LSP, and the label of the FEC information; and forwarding thefirst mLDP mapping message among received mLDP mapping messages thatbelong to the same FEC information, to the user-side root node.
 7. Themethod according to claim 6, wherein the generating a packet forwardingentry of the network-side root node according to an mLDP label in thefirst mLDP mapping message received by the network-side root node, theRSVP P2MP LSP, and the label of the FEC information comprises:associating the mLDP label in the first mLDP mapping message received bythe network-side root node with the RSVP P2MP LSP and the label of theFEC information, and generating the packet forwarding entry of thenetwork-side root node, wherein the mLDP label in the first mLDP mappingmessage received by the network-side root node is set as an incominglabel, and an RSVP label of a downstream node that sends the mLDPmapping message is set as an outgoing label, wherein the RSVP label ofthe downstream node that forwards the mLDP mapping message is allocatedwhen the RSVP P2MP LSP is established.
 8. The method according to claim6, wherein the method further comprises: receiving a firstmulti-protocol label switching packet from an upstream node, wherein thefirst multi-protocol label switching packet is encapsulated by theuser-side root node by using the mLDP label of the user-side leaf node;removing the mLDP label of the user-side leaf node from the firstmulti-protocol label switching packet to obtain a second multi-protocollabel switching packet; replicating the second multi-protocol labelswitching packet to obtain third multi-protocol label switching packets,wherein a number of third multi-protocol label switching packetsobtained by replicating the second multi-protocol label switching packetis equal to a number of outgoing labels in the packet forwarding entryof the network-side root node; and encapsulating the thirdmulti-protocol label switching packets by using the label of the FECinformation and a RSVP label of a downstream node that forwards the mLDPmapping message, to obtain a fourth multi-protocol label switchingpacket, wherein the label of the FEC information is used as an innerlabel, and the RSVP label of the downstream node that forwards the mLDPmapping message is used as an outer label, and sending the fourthmulti-protocol label switching packet to the downstream nodecorresponding to the RSVP label of the downstream node that forwards themLDP mapping message.
 9. A method for implementing point-to-multipointmulticast, wherein a multicast source communicates with multicastreceivers by using a network running mLDP and a network running RSVP,wherein the network running RSVP comprises a network-side root node andnetwork-side leaf nodes, the network-side root node is a PE node that isin the network running RSVP and is oriented to the multicast source, thenetwork-side leaf nodes are PE nodes that are in the network runningRSVP and are oriented to the multicast receivers, the network-side rootnode communicates with the multicast source by using the network runningmLDP, and the network-side leaf nodes communicate with the multicastreceivers by using the network running mLDP and wherein the networkrunning mLDP comprises a user-side root node and user-side leaf nodes,the user-side root node is a PE node that is in the network running mLDPand is oriented to the multicast source, and the user-side leaf nodesare PE nodes that are in the network running mLDP and are oriented tothe multicast receivers; and the method comprises: receiving, by thenetwork-side leaf node, a distribution message from the network-sideroot node, wherein the distribution message comprises FEC informationand a label of the FEC information; sending a response message to thenetwork-side root node; and using the label of the FEC information as anincoming label of a packet forwarding entry of the network-side leafnode.
 10. The method according to claim 9, wherein the receiving, by thenetwork-side leaf node, a distribution message from the network-sideroot node comprises: receiving, from an intermediate node, thedistribution message sent by the network-side root node; or after aconnection is established to the network-side root node on an RSVP P2MPLSP, receiving the distribution message directly from the network-sideroot node.
 11. The method according to claim 9, wherein the methodfurther comprises: receiving a first multi-protocol label switchingpacket from an upstream node; removing an RSVP label of the network-sideleaf node and the label of the FEC information from the firstmulti-protocol label switching packet to obtain a second multi-protocollabel switching packet, wherein the RSVP label of the network-side leafnode is allocated when the RSVP P2MP LSP is established; replicating thesecond multi-protocol label switching packet to obtain thirdmulti-protocol label switching packets, wherein a number of thirdmulti-protocol label switching packets obtained by replicating thesecond multi-protocol label switching packet is determined according toa number of mLDP labels of downstream nodes corresponding to the labelof the FEC information; and encapsulating the third multi-protocol labelswitching packet by using an mLDP label in an mLDP mapping message sentby a downstream node, to obtain a fourth multi-protocol label switchingpacket, and sending the fourth multi-protocol label switching packet tothe downstream node corresponding to the mLDP label of the downstreamnode.
 12. A network node comprising: a processor; a non-transitorycomputer readable medium connected to the processor and having storedthereon instructions that, when executed, cause the processor to:receive an mLDP mapping message from at least one downstreamnetwork-side leaf node, wherein each mLDP mapping message comprisesforwarding equivalence class FEC information and an mLDP label of anetwork-side leaf node that sends the mLDP mapping message; acquire anRSVP P2MP LSP according to the downstream nodes that send the mLDPmapping messages; allocate a label to the FEC information, and send thelabel of the FEC information to all the nodes that are on the RSVP P2MPLSP and that send the mLDP mapping messages; generate a packetforwarding entry of the network node and according to an mLDP label ofthe network node, the RSVP P2MP LSP, and the label of the FECinformation; and send a new mLDP mapping message to an upstream node,wherein the new mLDP mapping message comprises the FEC information andthe mLDP label of the network node, and wherein the FEC informationcomprises an address of a user-side root node.
 13. The network nodeaccording to claim 12, wherein non-transitory computer readable mediumfurther has instructions stored thereon, that when executed, cause theprocessor to perform at least one of: search for an existing RSVP P2MPLSP according to the downstream nodes that send the mLDP mappingmessages; or establish the RSVP P2MP LSP according to the downstreamnodes that send the mLDP mapping messages; wherein the RSVP P2MP LSPcomprises all the downstream nodes that send the mLDP mapping messages.14. The network node according to claim 12, wherein non-transitorycomputer readable medium further has instructions stored thereon, thatwhen executed, cause the processor to perform at least one of: send adistribution message that comprises the FEC information and the label ofthe FEC information to an intermediate node, so that the intermediatenode sends, after replicating the distribution message, the distributionmessage to all the nodes that are on the RSVP P2MP LSP and that send themLDP mapping messages; or after connections are established to all thenodes that are on the RSVP P2MP LSP and that send the mLDP mappingmessages, send a distribution message directly to all the nodes that areon the RSVP P2MP LSP and send the mLDP mapping messages, so that all thenodes that send the mLDP mapping messages use the label of the FECinformation as an incoming label of packet forwarding entries of thenodes.
 15. The network node according to claim 12, whereinnon-transitory computer readable medium further has instructions storedthereon, that when executed, cause the processor to: associate the mLDPlabel of the network node with the RSVP P2MP LSP and the label of theFEC information; and generate the packet forwarding entry of the networknode, wherein the mLDP label of the network node is set as an incominglabel, and an RSVP label of a downstream node that sends the mLDPmapping message is set as an outgoing label, wherein the RSVP label ofthe downstream node that sends the mLDP mapping message is allocatedwhen the RSVP P2MP LSP is established.
 16. The network node according toclaim 12, wherein non-transitory computer readable medium further hasinstructions stored thereon, that when executed, cause the processor to:receive a multi-protocol label switching packet from an upstream node,wherein the multi-protocol label switching packet is encapsulated by theuser-side root node by using an mLDP label of the network node; removethe mLDP label of the network node from the multi-protocol labelswitching packet; replicate the multi-protocol label switching packetwith the mLDP label removed, wherein a number of replicatedmulti-protocol label switching packets is equal to a number of outgoinglabels in the packet forwarding entry of the network node; encapsulatethe replicated multi-protocol label switching packets by using the labelof the FEC information and an RSVP label of a downstream node that sendsan mLDP mapping message, wherein the label of the FEC information isused as an inner label, and the RSVP label of the downstream node thatsends the mLDP mapping message is used as an outer label; and Send themulti-protocol label switching packet to the downstream nodecorresponding to the RSVP label of the downstream node that sends themLDP mapping message.
 17. A network node comprising: a processor; anon-transitory computer readable medium connected to the processor andhaving stored thereon instructions that, when executed, cause theprocessor to: receive an mLDP mapping message, which is sent by auser-side leaf node and forwarded by at least one downstream node;perform snooping on the received mLDP mapping message to acquire, fromthe mLDP mapping message, FEC information and an mLDP label of theuser-side leaf node to which the mLDP mapping message belongs; acquire aRSVP P2MP LSP; allocate a label to the FEC information; send the labelof the FEC information to all the nodes that are on the RSVP P2MP LSPand that forward the mLDP mapping messages; generate a packet forwardingentry of the network node according to an mLDP label in a first mLDPmapping message received by the network node, the RSVP P2MP LSP, and thelabel of the FEC information; and forward the first mLDP mapping messageamong received mLDP mapping messages that belong to the same FECinformation, to an upstream node.
 18. The network node according toclaim 17, wherein non-transitory computer readable medium further hasinstructions stored thereon, that when executed, cause the processor to:receive a multi-protocol label switching packet from an upstream node,wherein the multi-protocol label switching packet is encapsulated by auser-side root node by using the mLDP label of the user-side leaf node;remove the mLDP label of the user-side leaf node from the multi-protocollabel switching packet; send the multi-protocol label switching packetwith the mLDP label removed, to a second packet replicating unit; andreplicate the multi-protocol label switching packet with the mLDP labelremoved, wherein a number of replicated multi-protocol label switchingpackets is equal to a number of outgoing labels in the packet forwardingentry of the network node; encapsulate the replicated multi-protocollabel switching packets by using the label of the FEC information and anRSVP label of the downstream node that forwards the mLDP mappingmessage, wherein the label of the FEC information is used as an innerlabel, and the RSVP label of the downstream node that forwards the mLDPmapping message is used as an outer label; and send the multi-protocollabel switching packet to the downstream node corresponding to the RSVPlabel of the downstream node that forwards the mLDP mapping message. 19.A network node comprising: a processor; a non-transitory computerreadable medium connected to the processor and having stored thereoninstructions that, when executed, cause the processor to: receive, froman upstream node, a distribution message that comprises FEC informationand a label of the FEC information; send a response message to theupstream node that sends the distribution message; and use the label ofthe FEC information as an incoming label of a packet forwarding entry ofthe network node.
 20. The network node according to claim 19, whereinnon-transitory computer readable medium further has instructions storedthereon, that when executed, cause the processor to: receive amulti-protocol label switching packet from the upstream network-sideroot node; remove an RSVP label of the network node and the label of theFEC information from the multi-protocol label switching packet, whereinthe RSVP label of the network node is allocated when the RSVP P2MP LSPis established; replicate the multi-protocol label switching packet withthe RSVP label and the label of the FEC information removed, wherein anumber of replicated multi-protocol label switching packets isdetermined according to a number of mLDP labels of downstream nodescorresponding to the label of the FEC information; encapsulate thereplicated multi-protocol label switching packets by using an mLDP labelin an mLDP mapping message sent by a downstream node; and send themulti-protocol label switching packet to the downstream nodecorresponding to the mLDP label of the downstream node.